<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>

<div id="app">
  <button @click="add1">{{count1}}</button>
  <button @click="add2">{{count2}}</button>
  <button @click="add3">{{count3}}</button>
</div>
<script>
  const vm = new Vue({
    el: '#app',
    data: {
      count1: 0,
      count2: 0,
      count3: 0
    },
    methods: {
      add1() {
        this.count1++
      },
      add2() {
        this.count2++
      },
      add3() {
        this.count3++
      }
    }
  })
</script>